The present invention has for an object colorants for oxidative dyeing of keratin fibers, particularly human hair, containing 4-aminobiphenyl-3-ol derivatives.
In the area of keratin fiber dyeing, particularly hair dyeing, oxidation dyes have attained substantial importance. In this case, the coloration is produced by reaction of certain developers with certain couplers in the presence of an appropriate oxidant. Suitable developers are, in particular, 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, p-aminophenol, 1,4-diaminobenzene and 4,5-diamino-1-(2-hydroxyethyl)pyrazole, and suitable couplers are, for example, resorcinol, 2-methyl-resorcinol, 1-naphthol, 3-aminophenol, m-phenylenediamine, 2-amino-4-(2′-hydroxyethyl)amino-anisole, 1,3-diamino-4-(2′-hydroxyethoxy)benzene and 2,4-diamino-5-fluorotoluene.
The oxidation dyes used for dyeing human hair must meet numerous requirements in addition to producing hair colorations that are stable for at least 4 to 6 weeks. For example, these dyes must be harmless from a toxicological and dermatological standpoint, and the hair colorations obtained must have good light fastness, resistance to permanent waving, rubbing fastness and resistance to shampooing as well as sufficient resistance to perspiration. Moreover, by combining appropriate developers and couplers, it must be possible to create a wide range of different color shades.
The adjustment of lighter color shades presents a special problem in terms of uniform dye uptake from the hair roots to the hair tips and in terms of resistance of the colorations to permanent wave treatment. The use of direct yellow-dyeing aromatic nitro dyes together with oxidative hair dye precursors represents a partial solution of the said problem, but the stability of the colorations over a period of several weeks is often unsatisfactory.